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Rick Rieh:n on Trail Bike Area Noise Assessment 29 July 2005 Page 2 Continuously reading meters were also set up at two locations, the Neal Brueggemeier residence north of the trail area and the Paul Segner residences west of the trail area. Due to some Technical problems, data from the Brueggemeier location were not reliable. However, data from the Segner residence and the nine monitoring sites provided sufficient information for estimating sound levels at more remote .locations. The time history of the L 10 and L50 sound levels at the Segner residence is shown on Attachment 2. L50 is the level observed 50% of the time during each minute shown on the chart. Also shown (arbitrarily at the 42 dBA level) are the times that bikes were using the trail. The very high L10 level are associated with passing vehicles and not related to the trail. It can be seen that there is some correlation with activity.on the trail, with maximum L10 levels generally around 46 dBA with some peaks at 48 dBA. Sound levels with bike activity increased generally no more than 6 dBA during the course of the test. Estimated found Levels at Surrounding Residential Receptor Sites Sound levels from the trail were projected to each of 13 surrounding residential locations assuming attenuation with distance and atmospheric absorption, but limited attenuation from any topography or vegetation. Therefore, sound levels could be lower under calm conditions, lower with wind 'plowing towards the trail and higher with the wind blowing from the trail. L10 levels have been predicted for 3, 6, 12 and 24 bikes using the trail continuously for an hour. The 13 receptors, approximate distance from the center trail area, and predicted L101evels for 3 and 6 bib:es are shown in the table below. Location of the receptor sites is shown on Attachment 1. .Site Resident A .Dist ft) L10 (3 bikes) L10 (6 bikes 1 Unknown 2900 44 47 2 1289 Jennin s Ave. NW 1600 49 52 3 Ted Lee/Richard Riehm 2200 47 50 4 Paul Se per 2500 46 49 5 Jeff Schober 2000 48 51 6 tJno_cc_upied .__ --- 2500_ _ ~ --- ----- `-_~'r6 _- 49 7 ---- -Neal Brue Tvemeier 1900 4S ' 1 8 Harve En elman 2200 50 53 9 Ted Lorentz 3100 44 47 10 Albion 3300 44 47 I 1 Mike Horsch 3300 47 50 12 David Bowman 3700 46 49 13 (Tanned home 1200 53 56 L 10 Standard 65 65 The results for 3, 6, 12 and 24 bikes shown graphically on Attachment 3, although use of the track by the higher number of hikes will be limited. The general range of observed background sound level in the area is also shown on the attachment. Based upon the monitored noise levels and predictions based upon these levels, use of the trail bike area is not expected to generate sound levels over the Minnesota daytime noise standards. y: ;jobs\2005jobs\205064\riehm-0729-mem.doc -298-